1. Object of the Invention
This invention relates to an improved process for producing a 2-tertiary-alkyl substituted anthraquinone.
2. Description of the Prior Art
A process for producing a 2-tertiary-alkyl substituted anthraquinone, characterized by carrying out catalytic oxidation of a diphenylmethane type compound having the formula: ##STR2## wherein R.sub.1 and R.sub.2 are different from each other, and independently hydrogen or tertiary-alkyl having 4 or 5 carbon atoms with the proviso that one of R.sub.1 and R.sub.2 is hydrogen, and R.sub.3 is alkyl having 1-3 carbon atoms, in vapor phase in the presence of a catalyst containing vanadium oxide is disclosed in U.S. Pat. No. 4,036,861 dated July 19, 1977 which was assigned to the assignee of this application and which is incorporated herein.
A process for producing a 2-tertiary-alkyl substituted anthraquinone in a high yield with little or no formation of benzylbenzaldehyde is disclosed in U.S. Pat. No. 4,036,861. The catalyst disclosed in the U.S. Patent is vanadium oxide alone or combinations of vanadium oxide and other metal compounds. However, a catalyst composed of vanadium oxide alone or a mixture of vanadium oxide and other metal compounds has a relatively short life.